On the Influence of Time Delay Modelling in Grid-Connected Converters for Harmonic Studies

Increasing integration of converter connected components within the electric grid, such as renewable generation units and DC loads, lead to changes in the stationary and dynamic behaviour of electrical systems. Harmonic studies amongst others are conducted to maintain stable operation of the electric system. Therefore, sufficiently detailed converter models are required and are subject of current research. Time delay component, often simplified using Padé approximation, is usually introduced into the model to represent the computational delay of the microcontroller of the converter unit. The effects of this linear approximation and influence of the time delay modelling on the frequency-dependent impedances of the converter are investigated in this paper.